Technically you are right. Redeployment system cannot be used when engaged. He must had to spawn a vehicle and go away instead of redeploying. At the other hand don't tread on medics, there is not much player who would cope up to play on a boring faction. We wouldn't have a proper working R&R system that responds %80 of the dispaches if they had to stumble upon shit like this. You did not shown your intent to take him hostage, he just did what was suitiable. It doesn't seem like he avoided the sitation intentionally. You did not posted the dispute evidence video of the sitation but I can assume he would probably able to evade the sitation without redeploying. I mean he is above rank search and rescue. He is able to spawn ghosthawks,striders etc. vehicles that can run away from you easily before you arrive at the hospital.
Notes: Activate Windows